Discoveries in botany, the result of better knowledge of natural history and more accurate habits of study, have influenced{238} modern progress not a little; have led to better classification and broader knowledge. The natural system of de Candolle (1778-1841) of Geneva, and of Endlicher, of Vienna, called into existence the so-called natural historical school of medicine; the researches into plant-cells by Schleiden and Baumgartner, and the almost contemporaneous discovery of animal cells by Schwann became, in course of time, the origin of recent cellular pathology; then came microscopic botany, and the influence of the lower fungi in the production of fermentation and putrefaction. Similarly too, the laws of physics have been shown to have an inseparable connection with anatomy and physiology, and their study has become a most important aid in the experimental researches of to-day; through Helmholz they brought in the ophthalmoscope; thermal electricity, for the discovery of which medicine is indebted to Seebeck; a better knowledge of optics, thanks to Fraunhofer, who was equally expert in electricity; spectrum analysis, invented by Kirchhoff; and the varied efforts of Faraday, Graham Bell, Thomas Alva Edison, and Daguerre, the latter better known for his invention of photography. Finally, medicine is immeasurably indebted to Tyndall and Huxley for their teaching of the correlation and conservation of energy. Chemistry also has performed its share, and, as applied to physiology, is a discovery almost wholly within the present century. The new nomenclature serves a practical purpose in that it is now possible to portray chemical combinations and isomerism in a graphic, and at least, semi-comprehensive way. Among the chemists may be specially mentioned Bertholet, whose laws are as well known as they are succinct; Humboldt; Berzelius; Dumas; Chevreuil, who recently died at the age of almost one hundred years; Magendie; Orfila, the toxicologist; Gmelin, eminent in physiological chemistry; Rose, perfecter of organic analysis; Wohler,{239} who first made organic alkaloids; Bunsen; Sir Humphry Davy; Marsh; Faraday; Graham; Young, who first showed the industrial value of coal; and Gay-Lussac. Upon medicine, zoology also, with comparative anatomy and physiology, has had a wonderful influence; here may be noted the names of Cuvier, Oken, Bilharz, Brehm, Wagner, Leuckart, Richard Owen, William Carpenter, and last, but by no means least, Thomas Huxley.